Stage incubator for microscopes



Patented Apr. 27, 1948 STAGE INCUBATOR FOR MICROSCOPES Wilfred Homer and Eugene Wesselman, Chicago,

signors, by mesne assignments, to Beimont Radio Corporation, Chicago, 111., a corporation of Illinois Application September 11, 1944, Serial No. 553,661

Claims. 1

This invention relates to stage incubators for microscopes and more particularly to such stage incubators by means of which a, small and precisely predetermined volume of culture medium may be subjected, while in the microscope, to closely controlled variable conditions afiecting development of the culture, for example, a variable temperature, a variable electro-magnetic or electrostatic field, or a combination of these or different conditions.

It is often desirable in the microscopic investigation of the growth of bacteria, simple cellular organisms and like cultures in a medium, to be able to determine accurately the rate of propagation. This may be done by counting, from time to time, the number of units present in a precisely determined volume of the medium, preferably sufficiently small to permit counting di rectly or by dilution in a known volume and subsequent division and counting the number of units in a given fraction of the'original volume. It is also often desirable to be able accurately to control various conditions in the region of the culture afiecting its development, for example, its temperature, the magnitude of an electromagnetic field or an electrostatic field, or a combination of these or other conditions. No apparatus is at present available for securing these results and the present invention is directed to a stage incubator by meansof which such results may be obtained.

. microscopes including means for developing a closely controlled variable condition in the region and electromagnetic fields in 2 closed by transparent covers, such as cover glasses, engaging the faces of the web to form a container for a culture medium to be examined.

Further in accordance with the invention, a

4 culture medium stage incubator for microscopes comprises a base member having a configuration for mounting on a microscope and including a central web and an aperture in the web adapted to be closed by at least one transparent cover engaging a face of the web to form a container for a culture medium to be examined. The incubator also includes means for developing in the region of the aperture 8, variable condition afiecting the culture development.

For a better understanding of the invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings while its scope will be pointed out in the appended claims.

Referring now to the drawing, Fig. la is a perspective view, while Figs. lb and lo are cross sectional views, along the lines 5-? and c-c of Fig. la, of a stage incubator for micro-scopes embodying the invention and adapted for variations of temperature or of an electromagnetic field in the region of the culture: Fig. 2c. is a perspective view and Fig. 2b is a cross sectional view of a modified form of the stage incubator of the invention adapted for the development of a variable electrostatic field in the region of the culture; while Fig. 3 is a perspective view of a further modified form of the invention adapted for the development of combined variable electrostatic the region of the culture.

of the culture affecting its development, for example, its temperaturathe magnitude of an electromagnetic field or an electrostatic field, or a combination of these or other conditions.

In accordance with the invention, a culture medium stage incubator for microscopes comprises a base member having a configuration for mounting in a microscope and including a central web having parallel faces and a. small precisely climensioned aperture in the web adapted to be Referring now to Figs. lo, lb and 1c of the drawing, there is illustrated a culture medium stage incubator for microscopes comprising a base member I0 including a central cylindrical body portion Ifia of substantial thickness and an extended flange mo having'a configuration suitable for mounting in a microscope, preferably rectangular, as illustrated. The central body portion Illa has a, circular central web portion Hie of reduced thickness, preferably of a thickness only a small fraction of that of the body portion Ida and formed with substantially parallel upper and lower faces. A small precisely dimensioned aperture Hid, preferably circular, is formed in the web we and is adapted to be covered by a transparent cover means engaging one or both faces of the web lfic to form a container for the culture medium to be examined or observed in the microscope, transparent cover glasses I i being the region or the aperture dition aflecting the culture development; ror ex illustrated as cilia-81118 both top and bottom faces of the web lie in Fig. 1c.

The stage incubator also includes means disposed within the base member for developing in lld a variable conample, the bulk portion Ila may be formed with an annular groove lle surroundin the web portion Inc and the aperture lid and an electrical winding I01 may be out to terminals Illa connected to suitable electrical supply terminals 12 through suitable condisposed therein and brought 10' placed by a portion of similar configuration formtrol means such as an adjustable impedance or I resistor l3.

In case it is desired to develop an elevated temperature at aperture 10d, the winding I! is referably formed of high-resistance wire wound in a non-inductive iashion, for example, a bifllar winding, efiective to heat the body portion Illa and the web lllc and develop the desired elevated temperature at aperture d. On the other hand, if it is desired to observe the eiIects of an electromagnetic field on the culture medium in aperture Iii-the winding i0! is formed of a low-resistance conductor and wound in the usual inductive fashion.

The body portion Illa is preferably provided with a recess lilh adapted to receive a temperature-responsive element such as a thermometer or, as illustrated, a thermocouple. ll provided with terminals ila which may be connected to a suitable meter is to: giving an indication or the temperature of the body portion ltd, which will closely approximate that at the aperture ltd.

It is believed that the operation of the stage incubator will be apparent from the foregoing description. Briefly, the base member to is dising an integral part0! the base member. Similarly, the cover glasses ll may be made of suitable transparent plastic material.

In case it is desired to observe the development of the culture under the influence of an electrostatic fleld, the construction of Figs. 1a, 1b and 1c may be modified to that of Figs. 2a and 2b, in which the base member 20 comprises a square central body portion 20:; of substantial thickness, with an extending flange portioniilb of rectangular configuration suitable for mounting in a microscope. The body portion 20a is oi a substantial thickness and is provided with a square central web portion 200 having a central. precisely dimensioned square aperture 2012, the

thickness of the web We being only a small fraction of that of the body portion 26a. Disposed "on either side of the aperture 28d is a pair of posed in the microscope and positioned by the flange portion lb and a glass cover plate M is disposed to engage the lower face of the web portion lbc, preferably being of such a ti'ilckness that its lower face lies flush with that of the base member it. A small and known volume of cul= ture medium is deposited in the aperture ltd and a second cover plate it is then disposed on the upper face of the web We and closely engages this face so that any excess of culture medium deposited in the aperture ltd is squeezed out and a small, precisely predeteed volume of culture medium is ieit in the aperture Edd.

The medium in aperture Mid can then be inspected and observed in the microscope, usually being illuminated from beneath, and the course of development or change in the culture medium observed. also the development or the culture under varying degrees of temperature orunder varying magnetic fields can be observed by selecting the appropriate winding it)? and controlling energization thereof from the supply terminals l2 by means oi the adjustable resistor 63. In case the temperature of the medium is an important factor in the observations being made, the relatively large mass of the body portion lilo imparts a temperature-stabilizing effect due to its thermal inertia or heat-storage capacity; at the same time, the reduced cross-sectional area of the flange ibb s the conduction of heat to and from the body portion Mia and, thus,

7 length of which is comparable to the the efiectsoi extraneous heat sources on the body incubators oi Figs. 2a

parallel elongated electrodes at. In this construction, the base member is preferably formed of a plastic, or the like, because of its insulatin properties, in which case the electrodes 2! may be embedded in and extended through the body portion the. If electrical contact between the electrodes and the culture medium within the aperture is to be avoided, the electrodes 26 may be completely embedded in the body portion 280; and the web 2630 or they may be of a thickness equal to the thickness of the web 290 and define opposite sides or lated with a film oi lacquer, varnish or the like.

In case the electrodes 28 are short compared to the wave length of an alternating voltage supplied thereto, or in case a unidirectional voltage is supplied thereto, they are efiective to develop in the region of the aperture Edd an electrostatic field which may be controlled in any suitable nner, such as that described in connection with the arrangement of Fig. id to control the intensity of the electromagnetic held at aper= ture Edd.

In case it is desired to investigate the efiects of combined electrostatic and electromagnetic fields, the incubator of Fig. 2c may be modified to the form illustrated in Fig. 3, which is identical to that of Fig. 2a. except that the parallel electrodes 25' are considerably longer, preferably projecting through both sides of the body portion 28o. By exciting the electrodes 2i with an alter= noting-current signal of a frequency the wave length of the electrodes 29', these electrodes simulate an artificial two-wire transmission-line means which develops therebetween in the region including the aperture 2M combined electromagnetic and electrostatic fields. The manner of use of the stage and 3 is the same as that described above in connection with the species of Fig. la.

Thus, it is seen that by the constructions described above there is provided a smell, compact stage incubator with a small container or a prevcisely predetermined volume for reception of the culture medium. At the same time, the develop the aperture 26d and be insu-= I in practice:

ment of the culture medium may be readily observed under various conditions affecting its development by means of the arrangements for developing in the region of the aperture various culture-aflecting conditions.

While the stage incubator of the invention may take various forms and be constructed in various dimensions, there follows the principal dimensions of a stage incubator of the type illustrated in Fig. 1a, which has been found to be satisfactory Flange portion lob millimeters 50x78 Thickness do 2 Central body portion:

Diameter do 50 Thickness do 5 Central web portion:

Diameter do 25 Thickness do 050 Aperture diameter do..- 5 Volume cubic millimeters 9.8

While there have been present considered to ments of the invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit or scope of the invention.

What is claimed as new is:

1. A culture medium stage incubator for microscopes comprising, a base member having a configuration for mounting in a microscope and including a central web, an aperture in said web adapted to be closed by at least one transparent cover engaging a face of said web to form a container of accurately predetermined for a culture medium to be examined, and an winding disposed in said base member and surrounding said aperture for developing therein a cult ffecting condition.

2. A culture medium stage incubator for microscopes comprising, a base member having a configuration for mounting in a microscope and including a central web, an aperture in said web adapted to be closed by at least one transparent cover engaging a face of said web to form a container of accurately predetermined volume for a culture medium to be examined, and an electrical winding disposed in said ber and surrounding said aperture for developing therein an elevated temperature.

3. A culture medium stage incubator for microscopes comprising, a base member including a substantial thickness and mass having a central web and an extended flange of reduced thickness and having a configuration for mounting in a microscope, an aperture in said web adapted to be closed by at least one transparent cover engaging a face of described what are at be the preferred embodi- I 6 said web to form a container of accurately predetermined volume for a culture medium to be examined, and an electrical winding disposed in said base member and surrounding said aperture for developing therein an elevated temperature. the mass of said body portion and the reduced section of said flange imparting thermal stability to said body portion.

4. A culture medium stage incubator for microscopes comprising, a base member having a configuration for mounting in a microscope and including a central web, an aperture in said web adapted to be closed by at least one transparent cover engaging a face of said web to form a container of accurately predetermined volume for a culture medium to be examined, and an electrical winding disposed in said base member and surrounding said aperture for developing therein an electromagnetic field.

5. A culture medium stage incubator for microscopes comprising, a base member including a central cylindrical body portion of substantial thickness and an extended flange having a configuration for mounting in a microscope, said body portion having a central web portion of reduced thickness and substantially parallel faces, and a small precisely dimensioned aperture in said web adapted to be closed by transparent covers engaging the faces of said web to form a container of accurately predetermined'volume for a culture medium to be examined, said body portion being formed with an annular groove surrounding said web, and an electrical winding disposed in said groove for developing in the region of said aperture a culture-affecting conditicn.

WEIF'RED HORNEE. EUGENE WESSEHLMAN.

REFERENCES CITED The following references are of record in the file of this patent:

206,995 Great Britain Nov. 22, 1923 

